UK mega-retailer Tesco have posted an image of the back of the PC version of GTA IV's box today. The image doesn't reveal much, partly due to its tiny size and compressed nature, but I did pick out one interesting piece of text in the image:

"Initial activation requires internet connection"

It seems like you won't be able to play ANY of GTA IV unless you have your computer hooked up to the internet. This is becoming a common anti-piracy measure in PC games, but unlike the recently released Spore the boxart confirms that you will be able to install GTA IV an "unlimited" number of times.